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Immobilising Enzymes Immobilising Enzymes

Immobilising Enzymes - PowerPoint Presentation

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Immobilising Enzymes - PPT Presentation

64 Cloning amp Biotechnology Learning Objectives Understand the methods used for immobilising enzymes Understand the advantages of using immobilised enzymes Enzymes as Catalysts Enzymes are used to speed up chemical metabolic reactions eg respiration or photosynthesis so why use enzy ID: 615879

enzyme enzymes immobilised substrate enzymes enzyme substrate immobilised immobilising product products membrane temperatures molecules purification bonding mixture large catalyse

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Slide1

Immobilising Enzymes

6.4 Cloning & BiotechnologySlide2

Learning Objectives

Understand the methods used for immobilising enzymes.

Understand the advantages of using immobilised enzymes.Slide3

Enzymes as Catalysts

Enzymes are used to speed up chemical (metabolic) reactions e.g. respiration or photosynthesis- so why use enzymes in industry?

They are specific.

Can catalyse reactions between specific chemicals, even in a large mixture .

Form fewer bi-products.

Less purification needed.

Function well at relatively low temperatures saving money on fuel costs.

Enzymes from

thermophilic

bacteria can be extracted and used at high temperatures.Slide4

Isolating Enzymes

In some biotechnological processes, whole organisms are cultured to generate products, however when you need a single product, it is more efficient to isolate the enzyme

They can be isolated in large quantities

The extraction of enzymes from a fermentation mixture is known as

downstream processing

which is the

separation

and

purification of any product of large scale fermentationsSlide5

Immobilising Enzymes

Enzyme-substrate complexes must be formed in order to gain the products.

The easiest way is to mix the isolated enzyme with the substrate, however the product must then be separated which can be a costly process.

It is therefore possible to immobilise enzymes so they can catalyse the reaction without mixing freely.Slide6

Methods for Immobilising

Adsorption

Covalent Bonding

Entrapment

Membrane

Seperation

Slide7

Covalent Bonding

Enzyme molecules covalently bonded to a

support such as clay.

Cross-linking agent such as gluteraldehyde is used.

Binding is very strong.Slide8

Adsorption

Enzyme molecules are mixed with immobilising support e.g. glass beads or clay.

Hydrophobic interactions and ionic links form.

Enzymes

may

become detached, as links are weakSlide9

Membrane Separation

Substrate separated from the mixture by a partially permeable membrane.

Enzyme is on one side of the membrane, while the substrate is passed along the other side.

Substrate can pass through the mesh.Slide10

Entrapment

Enzymes trapped in their natural state in a gel bead

Reaction rate can be reduced as substrate needs to get through the trapping barrierSlide11

Advantages

Immobilised enzymes can be reused.

Product is enzyme free.

Immobilised enzymes are more tolerant to pH and temperature changes.

Enzyme not mixed with products so purification/ downstream processing costs are low.

Enzymes available immediately for re-use which is good for continuous processes.

The enzymes are more stable as the immobilising matrix protects the enzyme molecules – less likely to denature in extreme conditions.Slide12

Disadvantages

Additional time, equipment and materials needed, so expensive to set up.

Can be less active as they do not mix freely with the substrate.

Contamination can be costly if it occurs as the whole system needs to be stopped.Slide13

Examples of Immobilised Enzymes

Page 263 of the textbook has many examples of enzymes that immobilise for use in industry.

Write about 3 of them and how they are immobilised. Mention what reaction they catalyse.Slide14

Plenary

Why might bonding enzymes to a surface reduce their rate of activity?

Suggest why some immobilised enzyme processes can be carried out at temperatures well above the normal optimum for that enzyme.